There are, however, some earlier works reporting interesting physical properties due to the extended Ir 5\(d\)  orbitals. For instance, electronic structure calculations have predicted a metallic ground state in La\(_2\) CoIrO\(_6\) . But this was not confirmed by experimental results, which showed a FM-like insulating state for this Co- and Ir-based DP [1]}, [2]}. Further studies of this material revealed magnetodielectric effect together with re-entrant spin-glass behavior at low-\(T\)  [3]}, whereas Ca\(^{2+}\)  to La\(^{3+}\)  partial substitution leads to compensation temperatures and spontaneous exchange bias effect in La\(_{1.5}\) Ca\(_{0.5}\) CoIrO\(_6\)  (LCCIO) [4]}. For the case of Fe- and Ir-based DPs, the Ca\(^{2+}\)  to La\(^{3+}\)  partial substitution in La\(_{2-x}\) Ca\(_x\) FeIrO\(_6\)  induces interesting changes in the nature of the microscopic magnetic interactions between the TM ions, where the system evolves from antiferromagnetic (AFM) in the \(x\)  = 0 and 2.0 extremities of the series to FM-like in the \(x\)  \(\sim \)  1.0 intermediate region, this being ascribed to changes in Ir formal valence [5]}.
